From the mighty shark to the
humble frog, the world’s biodiversity is declining at unprecedented rates, say
scientists, based on what they say is the most comprehensive evaluation ever
conducted of the world's biodiversity.

The announcement was made at
the World Conservation Union's World Conservation Congress in Bangkok, Thailand,
this week. The findings are based on a report called the Global Species
Assessment, released by a consortium of conservation groups in conjunction with
the union's annual "Red List" of threatened species.

"There is some good news," said a
statement released by the World Conservation Union (WCU), an environmental
organization, this week regarding the findings. "Conservation measures are
already making a difference – a quarter of the world’s threatened birds have
benefited from such measures. What is needed is more of them, and to focus them
better."

The Global Species Assessment shows trends in
biodiversity over four years since the last major analysis in 2000, and it
includes, for the first time, complete assessments of amphibians, cycads (an
ancient group of plants) and conifers, as well as regional case studies. It also
highlights which species are at greatest risk of extinction, where they occur,
and the many threats facing them.

“Governments are starting to realise the
value of biodiversity and the critical role it plays in their peoples’
well-being. Species provide food, medicine, fuel, and building materials. They
help filter water, decompose waste, generate soil and pollinate crops.
Recognition of this is growing but governments need to mobilize far more
resources,” said David Brackett, Chairman of IUCN’s Species Survival
Commission.

In 1996 it was revealed that one in eight
birds (12%) and one in four mammals (23%) were threatened with extinction
(falling into the Critically Endangered, Endangered or Vulnerable categories).
This infamous line-up has now been joined by one in three amphibians (32%) and
almost half (42%) of turtles and tortoises, according to the World Conservation
Union.

With amphibians relying on freshwater, their
catastrophic decline is a warning about the state of the planet’s water
resources, the report said. Even though the situation in freshwater habitats is
less well known than for terrestrial, early signs show it is equally serious.
More than half (53%) of Madagascar’s freshwater fish are threatened with
extinction.

The vast ocean depths are providing little
refuge to many marine species which are being over-exploited to the point of
extinction. Nearly one in five (18%) of assessed sharks and rays are threatened.

Many plants have also been assessed, but only
conifers and cycads have been completely evaluated with 25% and 52% threatened
respectively.

For the first time, the assessment includes
the Red List Index, a new tool for measuring trends in extinction risk. This
shows overall changes in threat status (projected risk of extinction) over time
for a particular group. It will be important for measuring changes in
biodiversity. Red List Indices are currently available for birds and amphibians,
and show that their status has declined steadily since the 1980s.

“Although 15,589 species are known to be
threatened with extinction, this greatly underestimates the true number as only
a fraction of known species have been assessed. There is still much to be
discovered about key species-rich habitats, such as tropical forests, marine and
freshwater systems or particular groups, such as invertebrates, plants and
fungi, which make up the majority of biodiversity,” says Craig Hilton-Taylor,
the World Conservation Union’s Red List Programme Officer.

People, either directly or indirectly, are the
main reason for most species’ declines. Habitat destruction and degradation
are the leading threats but other significant pressures include
over-exploitation for food, pets, and medicine, introduced species, pollution
and disease. Climate change is increasingly recognised as a serious threat.

“It is clear that the situation facing our
species is serious and getting worse. We can continue to assess and bemoan the
loss of the world’s biodiversity or we can act! We must refocus and rethink
the way in which society must respond to this global threat,” says Achim
Steiner, the World Conservation Union's Director General.

“While most threats to biodiversity are
human-driven, human actions alone can prevent many species from becoming
extinct. There are many examples of species being brought back from the brink
including the southern white rhino and black-footed ferret, and thousands of
dedicated people around the world are doing their utmost to reverse the
extinction rate,” he added. “But this cannot continue to be the task of the
environmental community alone. Governments and business must commit to these
efforts as well”.

Since the release of the 2003 Red List, more
than 15,633 new entries have been added and 3,579 species reassessed. There are
now 7,266 threatened animal species and 8,323 threatened plant and lichen
species. A total of 784 plant and animal species are now recorded as Extinct
with a further 60 known only in cultivation or captivity.

Since 2003, there have been some notable
changes to the list, including some marked deteriorations, like the St Helena
olive (from Extinct in the Wild to Extinct), the Hawaiian crow (from Critically
Endangered to Extinct in the Wild), the Balearic shearwater (From Near
Threatened to Critically Endangered), the giant Hispaniolan galliwasp lizard
(from Near Threatened to Critically Endangered), and an African begonia, Begonia
oxyanthera (from Near Threatened to Vulnerable).

But there have also been some improvements,
such as the European otter (from Vulnerable to Near Threatened) and the
Christmas Island Imperial pigeon (from Critically Endangered to Vulnerable).

The 2004 assessment shows that threatened
species are often concentrated in densely populated areas, particularly in much
of Asia and parts of Africa. A major conservation challenge will therefore be to
reconcile the demands of large numbers of people on the environment, whilst
protecting the biodiversity upon which so many people’s livelihoods depend.

The importance of international support in
safeguarding biodiversity is critical says the assessment. Many countries with a
high concentration of threatened species have a low Gross National Income (GNI)
per capita and are unable to implement the required conservation measures
without international assistance.

Some key findings from the Global Species
Assessment

Numbers of threatened species are
increasing across almost all the major taxonomic groups.

The marine environment is not as well known
as the terrestrial environment but initial findings show that marine species
are just as vulnerable to extinction as their terrestrial counterparts.

Freshwater habitats are also poorly known,
but recent surveys reveal that many aquatic species are threatened with
extinction.

Most threatened birds, mammals, and
amphibians are located on the tropical continents - Central and South
America, Africa south of the Sahara, and tropical South and Southeast Asia.
These regions contain the tropical broadleaf forests which are believed to
harbour the majority of the earth’s living terrestrial and freshwater
species.